Avalanche, General Motor’s (NYSE:GM) Chevrolet-brand full size pickup truck that in 2003 was viewed as a trendsetting design, is getting one more year on the road before it disappears from the assembly line.

The model has not been redesigned or changed in any meaningful way since 2007, and reviews for that year’s model were anything but flattering or enticing to consumers.

The pickup, one of the oldest brands in the Chevy pickup lineup, at one point made up nearly 4% of Chevy’s overall sales, but has slowly slid down the hill, falling to just over 1% in 2009, Edmunds analyst Ivan Drury told USA Today.

In addition to lagging sales, the Avalanche is costing GM profit margin on each sale, as the average incentive on the pickup is around $5,329, well below GM’s average $3,227 incentive, and the industry pickup average of $2,157.

The Avalanche’s one remaining year won’t be without some fanfare, however, as the auto maker is coming to market with a 2013 Black Diamond Avalanche model to try and entice buyers to the last vehicle in the line. The Black Diamond is a special edition model that will come with body colored bed surrounds, and some additional features, including a rear camera, rear park assist, fog lamps and a remote starter.

The base model LS is anticipate to retail for $35,980, not including a $995 dealer freight charge.

After that, it’s all downhill.